Recorder



Nov. 27, 1945. L M swlF-r 2,389,828

RECORDER Filed Feb. 24, 1942 5 sheets-'sheet 1 lawrence/MIMI?? Z 4 .L M3 l; 1.l- W 4 n@l .5 nWVAF r a n O .Jv R A Rw! @MMU a l@ 1x -LxllC:

L. M. SWIFT Nov. 27, 1945.

RECORDER Filed Feb. 24. 1942 54 Sheets-Sheet 2 @www L. M. SWIFT Nov.27', 1945.

RECORDER Filed Feb. 24, 1942 5 Sheets-Sheet 3 7 A 46 1./ JNM RECORDERFiled Feb. 24, 1942 www [miem/MIMI?? Nov. 27, 1945. f

l.. M. swlFT RECORDER v Filed Feb. 24, 1942 5 Sheets-Sheet 5 klarem/ZM??WWIA Patented Nov. 27, 1945 UNITED STATES PATENT oFF1cE- RECORDERLawrence M. Swift, Tulsa, Okla., assignor to Engineering Laboratories,Incorporated, Tulsa, Okla., a corporation of Oklahoma ApplicationFebruary 24, 1942, Serial No. 432,143

1 Claim.

This invention relates to automatic recorders and more particularly toan apparatus adapted to rapidly and accurately record, simultaneously, aplurality of measurements.

Recorders have heretofore been constructed that would record a series ofmeasurements on the same recording sheet but all have been extremelycomplicated and very dii'licult to build and keep in adjustment. Most ofthese recorders have utilized a single meter or galvanometer andconnected this single meter or galvanometer, sequentially, into aplurality of input circuits. This necessitates the rapid switching ofwhat are often minute currents, causes the galvanometer to movethroughout its range rapidly and almost constantly and necessitates arepeated, compli cated moving of the marking stylus of the recorder.

The present invention provides a relatively simple, sturdy, easilyaccessible recorderwith a minimum of moving parts and switches, For thatreason, it is easy to construct, fast, reliable in operation andaccurate.

Basically, the recorder of this invention comprises a plurality ofmeasuring instruments, preferably galvanometers, arranged so that indi`cations of their measurements are all projected onto a common locus. Aphotocell is then arranged to continuously move back and forth acrossthis locus and with it a marking device is caused to move back and forthacross the recording surface. Then, as the photocell senses the crossingof one of the indications from one of the measuring instruments, themarking device is caused to make a mark on the recording surface. Thus,each time the photocell moves the length of the locus, a record is madeof the indication of each of the measuring instruments.

The apparatus of this invention preferably in corporates severaladditional features, such as an arrangement of the light source whichcauses the light from the measuring instrument to reach the locus in anelongated cross-sectional form which extends across the locus, thusmaking it easy to detect with the photocell and capable of.

slightly above the recording stylus. This permits the recording table tobe swung forward for easy access without interfering with the recordingstylus. A further feature is the manner in which the photocell ismounted on a reciprocable carriage with the recording stylus and itsoperating mechanism so that both may be reciprocated at the same time.There is also the feature of an adjustable slit which governs the actionof the photocell and makes possible extremely fine and accuratemeasurements. Still further, the carriage for the photocell and markingmechanism is mounted on a track which includes conductive rails throughwhich current to operate the marking mechanism is brought to themechanism. The currents from the photoce'll are taken from the carriagethrough a. flexible cable and a resiliently moved take-up wheel.

In addition to these features the marking mechanism is operated by aparticular type of electrical circuit so that the stylus does not wipeacross the recorder tape but merely makes the desired mark and isreleased.

All of these things cooperate to make the present recorder sturdy,trouble proof, accurate, and easily accessible for adjustment. Each isincluded in this invention but the invention is not limited to any oneof them.

For a more complete understanding of the apraratus of this invention andits numerous details and advantages reference may be had to theaccompanying drawings.

In the drawings:

Figure 1 is a front elevation of a recording apparatus embodying theprinciples of this invention; y

Figure 2 is a side elevation partly in section ofthe same apparatus; 4

Figure 3 is a rear elevation of the same apparatus with the casesectioned to reveal the internal parts;

Figure 4 is a side sectional elevation of the same apparatus taken online 4 4 of Figure 3;

Figure 5 is a detail View in rear sectional elevation of the sameapparatus taken along line 5-5 of Figure 3; f v

Figure 6 is a detail view in top plan taken along line 6-6 of Figure 5;

Figure 7 is a detail top sectional view taken along line 1-1 of Figure5; and

Figure 8 is a, circuit diagram of the recorder.

The recorder illustrated is mounted on a base l0 and enclosed in a casegenerally designated I l. This case has a hinged front portion I2 whichmay be opened to give4 access to the recording tape. mmsand otherinternal parts. The hinged front contains a transparent window i3through which the operation of the instrument may be observed.

At the rear ofthe base Ill ismounted an upctanding plate I4 whichcarries a multiple socket connection I5 and a multiple plug connectionI6..

The multiple socket connection is shown in the drawing as having sixpairs of connections, which -anism of the recorder as will behereinafter described. "I'he back of the case is cut away at I1 and I8to give access to the socket I5 and the plug I6.

Inside the case, the currents to bel measured are conveyed directly, 4bya series of insulated wires I9, to the strings of a multiplegalvanometer 20, each pair of contacts being connected to the oppositeends of one of the strings, in theI usual manner. The multiplegalvanometer is of the Y type often used in seismic surveying, andcomprises a series of galvanometer wires or strings, each carrying atiny mirror and suspended between the poles of a relatively powerfulmagnet. As a current passes through one of these wires or strings it isdeflected and the mirror it carries moved to an extent dependent uponthe magnitude of the current. Since galvanometers of this general typeare quite well known .they will not be further described.

Light for the galvanometer mirrors is supplied by a small electric lamp2l mounted in a housing 22. In order to cause the light reilected fromthe galvanometer mirrors to have a vertically elongated cross-sectionthe lamp 2l has a vertical lament and the vertical cross-section of theemitted light beam is accentuated by providing a cylindrical lens 23,which is curved in a, vertical direction but not ina lateral direction,in the frontfof the housing. A mirror 24 may be provided behind thelamp. The lamp housing is .mounted on a bracket. 25 which in turn ismounted on the base I8.

Light from the lamp 2l passes through the lens 23, is reflected from theseveral mirrors of the multiple galvanometer 20 back through the bracket25 which supports the lamp housing and onto the scanning mechanism andalso onto a scale 26 positioned just above the scanning mechanism. Thereare two arms 21 which extend upwardly from the base plate near the irontedge of the machine, to hold the recording table and other parts and thescale 26 is suspended from these arms by means of small brackets. Byplacing the transparent scale in the same plane as the photocellaperture, to be described, the indications thereon will exactlycorrespond to those that are to appear on the recording surface.

'I'he scanning mechanism consists of a boxlike carriage 28 mounted bymeans of rollers 29 on a laterally extending track 30, so that it canroll back and forth from one side to the other of the recordingapparatus. The track 30 is mountedV on the base IU. When the device isin operation the carriage is continuously reciprocated by means of achain and sprocket arrangement 3l, appropriately supported from the baseI0 and driven by a synchronous electrical motor 32. The chain of thechain and sprocket arrangement 3| carries a small pin 33 which rides ina slot 34 in a bar 35, which bar is screwed to thev carriage 28 at itsopposite ends. Thus as the chain and sprocket arrangement is driven andpin 33 passes around the sprocket with the chain, the carriage 28 isregularly reciprocated from one end to -the other of its track.

Within the carriage 28 is positioned a photocell 38 and an adjustableslit arrangement, shown in Figures 5 and 7, is built into the rear wallof the carriage 28 so that the amount of light reaching the photocellmay be adjusted. This adjustable slit arrangement consists of avertically elongated opening 31 in the rear wall of the carriage and apair of vertical shutters 38 positioned behind the opening 3 andarranged so that they can be adjusted by a thumbscrew 39 to close theopen-v ing, laterally,y to any desired extent. Thus the slit can be madeof any desired width and the iineness of the recording thereby adjusted.

Connections from the photocell 36 pass from the movable unit 28 throughconnections 40 and a iiexible cable 4I to a cable reel or wheel 42rotatably mounted on a spindle 43 which is supported by an arm 44 fromthe bracket 25. The cable reel 42 is resiliently urged to rotate in adirection that will take up the slack in the flexible cable 4I by a pairof spiral springs 45 which are insulated from each other and serve asconnectors between the conductors in the cable 4I and conductors 48which are connected to an ampliiier 41.

The output of the ampliiier 41 is connected through connections, shownonly in the circuit diagram of Figure 8, to a pair of conductive rails48 mounted on the track which supports the movable carriage, butinsulated therefrom and from each other. From these rails the outputcurrent of the amplifier is connected through brushes in the bottomofthe movable carriage to a solenoid 49 in the carriage, which solenoidoperates an armature 50 which carries at its upper end a marking stylus5| adapted to contact the paper on the recording table when the solenoidis energized. A spring 52 normally urges the armature away from thepaper and the solenoid, upon actuation, brings the armature and thestylus toward the paper.

The recording paper is carried by a recording table 53 which ispivotally mounted in the supporting arms 21 at 54 which is above thestylus but below the center of the recording table. A recording paper isfed from a roll 55, behind and at the lower end of the recording table,over the face of the recording table and onto a roller 56 at the upperend and behind the recording table. The paper is moved along therecording table by a synchronous electric motor 51 through the usualdriving connections.

.By reason of the peculiar mounting of the recording table, the front ofthe recording instrument may be opened, the table tilted forward andaccess thus had to the rolls, from which the recording paper is unrolledand onto which it is rolled after being used. Ihis greatly facilitatesthe changing of paper. lAt the same time it gives access to the internalparts of the device without removing the entire case.

As has already been explained the currents to be measured are conducteddirectly to the strings of the galvanometer. The operating currentspursue a somewhat more devious path, however, and hence it may be wellto trace them through the circuit diagram of Figure 8.

Current for the motor 51 which moves the recording paper may be broughtinto the recorder through one of the pairs of contacts of the plug I6and controlled by the switch 58, which has not been shown in thedrawings of the apparatus, but which may be positioned at any place onthe case, or otherwise, that is found convenient.

Current for the other parts of the recorder may be brought in throughthe same pair of contacts, if the same voltage and frequency is to beused, or, alternatively, may be brought in through the other pair ofcontacts as shown in Figure 8, if a different voltage or frequency is tobe used. This current may be controlled by a switch 59, which like theswitch 58 has not been shown in the detailed drawings but which may bepositioned anywhere convenient. The motor 32 which drives thereciprocable carriage may be connected to receive its current directlyfrom this source. A

power supply unit 60 may also receive its supply' current directly fromthis source.

The reasonfor showing separate connections for the chart driving motoris that it may be desirable to govern the speed of the chart drivingmotor in accordance with some outside factor such as the passage oftime, the progress of a product past the measuring instruments, the rateof lowering a well surveying instrument in a drill hole, or the like.Any of these things can easily be used to control the movement of thechartif so desired.

In the power supply unit there may be positioned a small'transformer 6|to supply power to the lamp 2| and a second transformer G2, operating inconjunction with the usual rectifier tube 63, condensers, chokes and thelike to supply operating current to the photocell circuit.

The photocell circuit 41 is of novel construction. Voltage from thepower supply is applied through a resistor 64 across a voltage regulatortube 65 andl also across a circuit consisting of the photocell 36 and aresistor 6B. Thus the voltage across the photocell is carefully keptconstant, except as affected by the changes in the photocell itself. Oneof the grids of a Thyratron tube 51 is connected to this circuit betweenthe photocell 36 and the resistor 66 in such a manner that the'I'hyratron tube is tripped by the reduction of the resistance of thephotocell that is caused when light strikes the photocell. The plate ofthe Thyratron tube is connected through the solenoid 49 which operatesin the marking stylus and through a resistor 58 to the power pack. Thescreen grid of the Thyratron tube is connected to its cathode and thecathode is given the desired potential by connecting it to the slidero1' a potentiometer 69 which is connected across the output of the powerpack. A condenser I is conicted between the screen grid and the resistorWith this circuit, actuation of the photocell causes an increase in thevoltage` on the control grid, thus causing current to pass through theThyratron tube and operate the kmarking device. At this time, however,the condenser 10 discharges through the Thyratron tube and thepotentials of the screen grid and plate fall to a suiciently low voltageto stop the flow of current through the tube. Thus the marking stylus isimmediately released and will not be again operated until suicient timehas elapsed for the condenser 10 to again become charged from the powersupply, through the resistor 68. By properly proportioning the condenserand resistance this period may be made suiiiciently long so that thephotocell slit will have passed beyond the light beam which actuated it.Thus the marking device will make a single sharp mark for eachindication and all tendency toward the wiping of the markingstylusacross the record surface will be eliminated.

I claim:

Apparatus for recording simultaneously on a single record sheet aplurality of measurements comprising a source of light in xed position,a plurality of iixedly positioned galvanometers each of which isresponsive to anindependent source of energy and each of which includesa mirror y which is rotatable in response to electrical signals, theangular displacement of the mirrors being proportional to the intensityof the source of energy, each of said mirrors receiving light from saidsource of light and reflecting a beam in a direction dependent upon theinstantaneous position of the mirror, the reected beams from all themirrors of said galvanometer being in substantially the same plane, andthe field of the projected beam from each mirror being displaced fromthe eld of the projected beam from the other mirrors so that the beamsdo not overlap, a carriage, a photoelectric means carried by saidcarriage, means for moving the carriage continuously back and forth at auniform rate so that the photoelectric means is moved back and forthalong the line of said beams of light and continuously and repeatedlyscans the beams and produces electrical current upon the interception ofa beam, the record sheet being moved at right angles to the direction ofmovement of the carriage, a marking means carried by said carriage in aposition to make a mark on the record sheet when the marking means isenergized, said marking means being energized in response to thegeneration of said electrical currents by said photoelectric means, andthereby producing marks on the record sheet that are representative ofthe angular position of each of the mirrors at the instant at which thephotoelectric means intercepts a beam.

LAWRENCE M. SWIFT.

